What is the basic difference between a human brain and an animal brain? Well, one of the most captivating questions is found to be the most difficult to answer by neuroscientists until now. An international team of 34 scientists has identified a new type of brain cell in humans not found in other well-studied species.
As said by Ed Lein, Ph.D., Investigator at the Allen Institute for Brain Science “We really don’t understand what makes the human brain special. And now we have new tools to do just that.”
The discovery of the Rosehip Neurons has been reported in the journal Nature Neuroscience on August 27. It describes the newest neuron as very bushy and has long branches called dendrites which are very compact with lots of branch points and hence the name ‘Rosehip Neuron’.
To explain what is Rosehip? Rosehips are a kind of fruit that is produced by rose plants and the new neuron is named after this red fruit. To add to the new neuron’s appearance; Rosehip Neurons are like large bulbs at the end of their axons that release neurotransmitters or chemical signals to other neurons.
Rosehip Neurons are inhibitory neurons that form synapses with pyramidal neurons, the primary excitatory neurons in the prefrontal cortex. “We all have inhibitory neurons and excitatory neurons,” says Bakken, “but this particular type of inhibitory neuron is what’s new in this study. It’s especially based on its shape and its connections and also the genes that it expresses.”
“If we want to understand how the human brain works, we need to study humans or closely related species,” – says Trygve Bakken, co-author of the paper and a neuroscientist at the Allen Institute for Brain Science.
The type of information Rosehip Neurons control, and why they appear particular to humans, is yet to be discovered. It has the possibility to sort and manipulate the circuit in a really targeted way, but how that influences behavior will be investigated in later works as said by Bakken.
The new neuron has been documented by the researchers at the Allen Institute. While examining the researchers found a new neuron and when they looked at the genes of the Rosehip Neuron, they found that the neurons acted differently.
Whereas another team advanced its investigation by learning the electrical activity and shapes of neurons in brain tissues that were kept alive in a chemical solution after it was removed.
The major reason that neuroscientists were so long not able to discover this new neuron is because the cells are very rare in the brain and also because human brain tissues are difficult to obtain for study. For now, researchers have only studied one layer of the brain thus keeping high possibilities that Rosehip Neurons could be found in other layers too.
The difference between Humans and Animals
A cortex is present in all mammals and within it a neocortex but there are about a thousand times more cells in the human cortex compared to the mouse and this makes the basic difference. In other words, it makes up a much bigger part of our brain than it does a mouse’s and this might be the reason that researchers were unable to find any hint of Rosehip Neurons in mice.
This concludes that the nonexistence of the new neuron in mice’s brains provides a clear hint that the outcome of some brain studies done on rats cannot be trusted by humans.